Image Forming Apparatus Temperature Controller Aging Toner

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Solution Overview

Problem

The variation in heat characteristics of toner, such as glass transition temperature (Tg) and melting temperature (Tm), can lead to fixing offset issues, especially when toner values approach the upper or lower limits of the allowable range, and the use of low-temperature fixing toners further complicates this due to aging effects, resulting in insufficient margin for energy-efficient fixing processes.

Innovation Solution

An image forming apparatus with a temperature controller that adjusts the fixing temperature based on the elapsed time since the developer's manufacturing and its heat characteristics, using stored information to determine correction values from tables correlating elapsed days and heat characteristic classes to ensure optimal fixing conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If low-temperature fixing toner is used to save energy, then energy consumption is reduced, but fixing offset occurs due to aging-induced increase in glass transition temperature

Engineering Contradiction:
Improveenergy consumptionVSAvoidfixing offset occurrence
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the fixing temperature based on the elapsed time since developer manufacturing. The temperature controller modifies the fixing temperature parameter according to stored time information and heat characteristic data, compensating for aging effects while maintaining energy efficiency. This resolves the contradiction by allowing low-temperature fixing initially while progressively increasing temperature as aging occurs.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements preliminary action by storing manufacturing time information and heat characteristic values (Tg, Tm) in the developer container before use. The system proactively retrieves this information and pre-calculates appropriate fixing temperature adjustments based on elapsed time, preventing fixing offset before it occurs rather than reacting after the problem manifests.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If fixing temperature is optimized for toner at median heat characteristic values, then fixing quality is improved, but margin becomes insufficient for toner at upper and lower heat characteristic limits

Engineering Contradiction:
Improvefixing qualityVSAvoidadaptability to heat characteristic variation
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by providing customized fixing temperature settings for different heat characteristic ranges. Instead of a single uniform temperature optimization, the system stores multiple heat characteristic values (Tg, Tm) and retrieves appropriate correction values based on the specific developer batch's characteristics. This allows optimal fixing quality for each local heat characteristic condition while maintaining adaptability across variations.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by making the fixing temperature adaptive rather than static. The temperature controller dynamically adjusts the fixing temperature based on the elapsed time since manufacturing and the specific heat characteristic values of the developer batch. This dynamic adjustment ensures both optimal fixing quality and sufficient margin across the full range of heat characteristic variations.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If fixed manufacturing and fixing conditions are used, then device complexity is reduced, but fixing offset occurs due to heat characteristic variation and aging

Engineering Contradiction:
Improvecontrol system complexityVSAvoidfixing offset occurrence
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies self-service by enabling the developer container to store its own manufacturing time information and heat characteristic values (Tg, Tm). The container essentially serves itself by providing this information to the temperature controller, which then autonomously determines the appropriate fixing temperature adjustments. This maintains simplicity while improving reliability through automated, information-driven temperature control.

Inventive Principle:
Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach effectively reduces the occurrence of fixing offset by dynamically adjusting the fixing temperature, maintaining a sufficient margin regardless of changes in toner heat characteristics over time, even with low-temperature toners, thereby enhancing energy efficiency and preventing image defects.

Implementation Method 1

a fixing unit configured to perform the fixing process of developer transferred to a sheet by applying heat to the sheet

Methodology Applied
Scientific EffectHeat: Heating

Data Source

PatentEP3745212B1Image forming apparatus and a method of operating an image forming apparatus
Publication Date: 2023.08.23 TOSHIBA TEC KK
  • EP3745212B1 patent drawingFigure 1
  • EP3745212B1 patent drawingFigure 2
  • EP3745212B1 patent drawingFigure 3

AI summary

An image forming apparatus of the embodiment has a fixing unit and a temperature controller. The fixing unit performs the fixing process of developer transferred to a sheet by applying heat to the sheet at a predetermined fixing temperature. The temperature controller corrects the fixing temperature in the fixing process based on information indicating the manufacturing time of the developer.